Molecular mechanisms of the biphasic effects of interferon-γ on osteoclastogenesis

Academic Article

Abstract

  • Although interferon-γ (IFN-γ) potently inhibits osteoclastogenesis, the suppressive effect is significantly reduced when osteoclast precursors are pre-exposed to the receptor activator of NF-κB (RANK) ligand (RANKL). However, the molecular mechanism underlying the biphasic effects of IFN-γ on osteoclastogenesis remains elusive. Here, we recapitulate the biphasic functions of IFN-γ in osteoclastogenesis in both tissue culture dishes and on bone slices. We further demonstrate that IFN-γ markedly suppresses the RANKL-induced expression of nuclear factor of activated T-cells c1 (NFATc1) in normal, but not RANKL-pretreated bone marrow macrophages (BMMs). Similarly, IFN-γ impairs the activation of the nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) pathways in normal, but not RANKL-pretreated, BMMs. These findings indicate that IFN-γ inhibits osteoclastogenesis partially by suppressing the expression of NFATc1 and the activation of the NF-κB and JNK pathways. Moreover, IFN-γ inhibits the RANKL-induced expression of osteoclast genes, but RANKL pretreatment reprograms osteoclast genes into a state in which they can no longer be suppressed by IFN-γ, indicating that IFN-γ inhibits osteoclastogenesis by blocking the expression of osteoclast genes. Finally, the IVVY motif in the cytoplasmic domain of RANK is responsible for rendering BMMs refractory to the inhibitory effect of IFN-γ. Taken together, these findings provide important mechanistic insights into the biphasic effects of IFN-γ on osteoclastogenesis. © Copyright 2012, Mary Ann Liebert, Inc. 535-538
  • Digital Object Identifier (doi)

    Author List

  • Cheng J; Liu J; Shi Z; Jules J; Xu D; Luo S; Wei S; Feng X
  • Start Page

  • 34
  • End Page

  • 45
  • Volume

  • 32
  • Issue

  • 1